Apparatus for the automatic filling of motor vehicle tires

Abstract

A tire-filling system has an electronic control unit response to the tire pressure and the vehicle operating conditions for automatically operating pneumatic tire-filling valves to increase or reduce the tire pressure to setpoint values determined by the electronic control unit and matching the driving conditions. The pressure is delivered from a variable volume source in which a control element increases or decreases the volume. The system can be operated as an open system or a closed system.

1. A compressor-free device for the automatic actuation of a tire-filling apparatus for motor vehicles, comprising an electronic controller which, via sensors or with a logic unit determines the driving conditions and the tire pressure of all of the tires and controls pneumatic valves to match the tire pressure to at least such driving conditions as vehicle speed, vehicle loading, road conditions and terrain, wherein a control element is provided for increasing and decreasing a variable supply volume of a piston-and-cylinder arrangement for taking up air and supplying air for said apparatus, thereby matching internal tire pressure to a setpoint value therefor as determined by said controller, said piston-and-cylinder arrangement being the sole source of air for said tires in automatic operation of the apparatus. 
   
   
     2. The tire-filling apparatus defined in  claim 1  wherein the tire-filling apparatus is provided with a system of fluid lines between said source and said valves and said system is operable as a closed system disconnected from the ambient atmosphere. 
   
   
     3. The tire-filling apparatus defined in  claim 1  wherein said pneumatic valves are fed by at least one filling valve through respective sealing packets and respective filling lines. 
   
   
     4. The tire-filling apparatus defined in  claim 3  wherein said pneumatic valves are operated by respective control lines pressurized and vented by a separate pressurization element. 
   
   
     5. A compressor-free tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, said apparatus comprising:
 a source of a fluid under pressure in the form of a cylinder containing a variable supply volume of the fluid;  
 respective pneumatic valves for said tires actuatable to control an internal tire pressure thereof and connected between said source and the respective tire;  
 an electronic controller provided with inputs representing an actual pressure of said tires and at least one driving condition including vehicle speed, vehicle loading, road conditions and terrain, and determining setpoint pressures for said tires, said electronic controller having an output for operating said valves; and  
 a control element connected to said source for increasing and decreasing a variable volume for said apparatus, thereby matching internal tire pressure to a setpoint pressure therefor as determined by said controller.  
 
   
   
     6. The tire-filling apparatus defined in  claim 5  wherein said variable volume is enclosed in a gas-tight envelope. 
   
   
     7. The tire-filling apparatus defined in  claim 6  wherein said control element includes an electric motor. 
   
   
     8. The tire-filling apparatus defined in  claim 7  wherein said electric motor is a stepping motor. 
   
   
     9. The tire-filling apparatus defined in  claim 7  wherein said control element includes a transmission. 
   
   
     10. A tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, said apparatus comprising:
 a source of a fluid under pressure;  
 respective pneumatic valves for said tires actuatable to control an internal tire pressure thereof and connected between said source and the respective tire;  
 an electronic controller provided with inputs representing an actual pressure of said tires and at least one driving condition including vehicle speed, vehicle loading, road conditions and terrain, and determining setpoint pressures for said tires, said electronic controller having an output for operating said valves;  
 a control element connected to said source for increasing and decreasing a variable volume for said apparatus, thereby matching internal tire pressure to a setpoint pressure therefor as determined by said controller;  
 a system of fluid lines between said source and said valves; and  
 another valve connected to said lines, operated by said controller and enabling ambient air to be drawn into said system to compensate leakage therefrom and replenish a significant pressure loss in a tire.  
 
   
   
     11. A tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, said apparatus comprising:
 a source of a fluid under pressure;  
 respective pneumatic valves for said tires actuatable to control an internal tire pressure thereof and connected between said source and the respective tire;  
 an electronic controller provided with inputs representing an actual pressure of said tires and at least one driving condition including vehicle speed, vehicle loading, road conditions and terrain, and determining setpoint pressures for said tires, said electronic controller having an output for operating said valves;  
 a control element connected to said source for increasing and decreasing a variable volume for said apparatus, thereby matching internal tire pressure to a setpoint pressure therefor as determined by said controller;  
 a system of fluid lines between said source and said valves and said system is operable as a closed system disconnected from the ambient atmosphere;  
 replaceable fluid pressure cartridge; and  
 a further valve operated by said controller and connecting said cartridge to said system upon detection of a critical filling state of said system, whereby said closed system is automatically restored to a setpoint filling state.  
 
   
   
     12. The tire-filling apparatus defined in  claim 11 , further comprising a three-way valve connected to said system and having a port through which another system can be supplied with pressurized gas. 
   
   
     13. The tire-filling apparatus defined in  claim 11 , further comprising a vent connectable to said closed system and enabling a variable volume corresponding at least to a volume of said lines to be vented from said system. 
   
   
     14. The tire-filling apparatus defined in  claim 11  wherein said electronic controller is connectable to at least one control valve for piloting said pneumatic valves and at least one filling valve for supplying fluid under pressure to said pneumatic for delivery to the respective tire. 
   
   
     15. A device for the automatic actuation of a tire-filling apparatus for motor vehicles, comprising an electronic controller which, via sensors or with a logic unit determines the driving conditions and the tire pressure of all of the tires and controls pneumatic valves to match the tire pressure to at least such driving conditions as vehicle speed, vehicle loading, road conditions and terrain, wherein a control element is provided for increasing and decreasing a variable volume for said apparatus, thereby matching internal tire pressure to a setpoint value therefor as determined by said controller, said pneumatic valves being fed by at least one filling valve through respective sealing packets and respective filling lines, said pneumatic valves being operated by respective control lines pressurized and vented by a separate pressurization element in the form of a pneumatic cylinder. 
   
   
     16. A method of operating a tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, comprising the steps of:
 a) measuring an internal tire pressure at each of said tires;  
 b) determining at least one operating condition of the vehicle;  
 c) logically combining measurements of internal tire pressure and information with respect to an operating condition of such vehicle to determine a setpoint pressure for each of said tires;  
 d) generating a pressure exclusively by displacing a piston in a cylinder for increasing and decreasing variable volume; and  
 e) applying the pressure generated in step (d) to each of said tires until said setpoint is reached or venting excess pressure from each of said tires until said setpoint pressure is reached.